IllegalArgumentException occurs when the user enters an invalid port on the login screen.

### ⚠️ Before posting ⚠️

- [x] This is a **bug**, not a question or an enhancement.
- [x] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [x] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

Attempt to log in using an invalid port number, e.g., 10.0.2.2: 550021.

### Expected behaviour

The app should handle the port number and display a user-friendly error message indicating the port is invalid or out of range.

### Actual behaviour

The app throws an IllegalArgumentException and crashes instead of handling the error gracefully.

### Android version

15

### Device brand and model

Android Emulator

### Stock or custom OS?

Stock

### Nextcloud android app version

3.31.0

### Nextcloud server version

31.0.0

### Using a reverse proxy?

I don't know

### Android logs

`java.lang.IllegalArgumentException: port out of range:550021`

### Server error logs

```bash

```

### Additional information

_No response_